This allows the BL31 port to run with position-independent execution
enabled so that it can be ran from any address in the system.
This increases the flexibility of the image, allowing it to be ran from
other locations rather than only its hardcoded absolute address
(currently set to the typical DRAM base of 2GB). This may be useful for
future images that describe system configurations with other memory
layouts (e.g. where SRAM is included).
It does this by setting ENABLE_PIE=1 and changing the absolute
address to 0. The load address of bl31.bin can then be specified by
the -l [load address] argument in the fpga-run command (additionally,
this address is required by any preceding payloads that specify the
start address. For ELF payloads this is usually extracted automatically
by reading the entrypoint address in the header, however bl31.bin is a
different file format so has this additional dependency).
Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: Idd74787796ab0cf605fe2701163d9c4b3223a143
This initializes the GIC using the Arm GIC drivers in TF-A.
The initial FPGA image uses a GIC600 implementation, and so that its
power controller is enabled, this platform port calls the corresponding
implementation-specific routines.
Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: I88d5a073eead4b653b1ca73273182cd98a95e4c5
This adds a basic PSCI implementation allow secondary CPUs to be
released from an initial state and continue through to the warm boot
entrypoint.
Each secondary CPU is kept in a holding pen, whereby it polls the value
representing its hold state, by reading this from an array that acts as
a table for all the PEs. The hold states are initially set to 0 for all
cores to indicate that the executing core should continue polling.
To prevent the secondary CPUs from interfering with the platform's
initialization, they are only updated by the primary CPU once the cold
boot sequence has completed and fpga_pwr_domain_on(mpidr) is called.
The polling target CPU will then read 1 (which indicates that it should
branch to the warm reset entrypoint) and then jump to that address
rather than continue polling.
In addition to the initial polling behaviour of the secondary CPUs
before their warm boot reset sequence, they are also placed in a
low-power wfe() state at the end of each poll; accordingly, the PSCI
fpga_pwr_domain_on(mpidr) function also signals an event to all cores
(after updating the target CPU's hold entry) to wake them from this
state, allowing any secondary CPUs that are still polling to check
their hold state again.
This method is in accordance with both the PSCI and Linux kernel
recommendations, as the lessened overhead reduces the energy
consumption associated with the busy-loop.
The table of hold entries is implemented by a global array as shared SRAM
(which is used by other platforms in similar implementations) is not
available on the FPGA images.
Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: I65cfd1892f8be1dfcb285f0e1e94e7a9870cdf5a
This adds the minimal functions and definitions to create a basic
BL31 port for an initial FPGA image, in order for the port to be
uploaded to one the FPGA boards operated by an internal group within
Arm, such that BL31 runs as a payload for an image.
Future changes will enable the port for a wide range of system
configurations running on the FPGA boards to ensure compatibility with
multiple FPGA images.
It is expected that this will replace the FPGA fork of the Linux kernel
bootwrapper by performing similar secure-world initialization and setup
through the use of drivers and other well-established methods, before
passing control to the kernel, which will act as the BL33 payload and
run in EL2NS.
This change introduces a basic, loadable port with the console
initialized by setting the baud rate and base address of the UART as
configured by the Zeus image.
It is a BL31-only port, and RESET_TO_BL31 is enabled to reflect this.
Signed-off-by: Oliver Swede <oli.swede@arm.com>
Change-Id: I1817ad81be00afddcdbbda1ab70eb697203178e2
Oliver Swede